After weeks of speculation, Mack Brown made it official on Monday - there will be wholesale changes to the Texas Longhorn football staff.

Texas announced through a press release on Monday morning that offensive coordinator Greg Davis has resigned, while offensive line coach Mac McWhorter and defensive tackles coach Mike Tolleson have both retired. McWhorter and Tolleson's retirements and Davis' resignation will be effective August 31, 2011, but a search for their replacements will begin immediately.

The moves come in the wake of a disappointing 5-7 season that will see Texas at home during bowl season for the first time in Mack Brown's 13 years in Austin. Those struggles are even more shocking when pre-season expectations, which had Texas competing for a conference or even national title, are factored into the equation.

Rumors began swirling during the Longhorns' late-season swoon that changes may be on the way with hopes of jump-starting a Texas offense that staggered through most of the 2010 season. The primary target of the criticism was Davis, the architect of several record-setting offenses at Texas, but also the man saddled with the 2010 struggles that saw the Longhorns fail to top 24 points in nine of their final 10 games. On Monday, the news of wholesale changes became official.

"These are three special people who have given a lot of themselves and their families to The University of Texas and its football program," Brown said. "We appreciate everything they've done to help us have such great success during their lengthy stays with our staff at Texas. When you look at the last six years, especially - winning a National Championship in 2005, finishing No. 3 in 2008 and then being the runner-up after a tough loss to Alabama last year - it's just amazing what they've helped us accomplish.

"They are not only great coaches, but men who handled themselves with tremendous integrity, class and dignity on and off the field during their time here. I want to say thank you and wish them well because they will be missed."

With Davis' resignation, Brown and Davis will split a long-standing working relationship that goes back to the pair's days at Tulane. When Brown took over the Tulane program in 1985, he brought Davis in as his offensive coordinator and Davis would eventually succeed Brown as Tulane head coach when Brown moved on to North Carolina.

In 1995, after four years by Davis coaching at Tulane and brief OC stops at Arkansas and Georgia, Brown again came calling. Davis joined Brown at North Carolina, taking over the offensive coordinator duties, and the two have been linked ever since.

In his 13 seasons in Austin, Davis re-wrote the offensive record books. The 38-year coaching veteran oversaw the top nine scoring offenses in Texas history. His 2005 offense set a then-NCAA record for points scored in a season (652) and averaged a school-record 50.2 points per game during an undefeated national championship run. During his Longhorn career, Davis' offenses produced five Big 12 Offensive Players of the Year in Ricky Williams, Major Applewhite, Vince Young and two-time winner Colt McCoy. Two of his quarterbacks (Young and McCoy) finished as runner up for the Heisman Trophy.

"I've had a great 13 years here and enjoyed every minute of it," Davis said. "It's a tremendous university with great people, and I wish them nothing but the best. It's been a pleasure working with not only all of the great quarterbacks I've been fortunate enough to coach, but all of the terrific young men on both sides of the ball. I will miss all of the players, coaches and staff, but will always have great memories of the success the players and teams I was a part of were able to achieve at Texas."

In the first 12 years in Austin, Davis' offenses averaged 38.6 points per game. But the wheels came off in 2010, with the Texas offense averaging just 23.8 points per game, the fewest since Texas averaged 17.7 points in 1991. Texas struggled in the red zone, the transition to quarterback Garrett Gilbert was rocky and the offense was unable to get consistent production from the ground game. In a season filled with low points, the basement might have come in losses to Iowa State and Kansas State. Against ISU, Texas managed only six points before tacking on a couple fourth-quarter touchdowns to make the score more respectable. It was a similar story against KSU, with the Longhorn offense getting shut out for three quarters before putting up two meaningless scores late in the game.

With Davis out, Texas will likely look to make a hire that will meet a few objectives. First and foremost, Brown will bring in a coach that he feels can make an immediate turnaround in the offense's production. Beyond that, the new hire will be counted on to regain some of the momentum within the program that Texas lost in 2010, both inside the locker room and in recruiting.

McWhorter spent nine years coaching the Longhorn offensive line and also held the title of Associate Head Coach from 2005-2010. His offensive lines have paved the way for some of Texas' most successful offenses in the history of the program, but McWhorter has heard criticism in recent years for the Longhorns' struggles in developing a consistent ground game. In 2010, the Texas line was forced to break in new starters at right tackle and right guard, and the line was ravaged by injuries over the course of the year. Texas was able to finish seventh in the Big 12 in rushing yardage (150 yards per game) and third in the conference in giving up just 18 sacks.

Five of the Texas linemen McWhorter has tutored are currently in the NFL, and seven have earned All-America honors on nine occasions with OT Jonathan Scott and OG/T Justin Blalock each garnering that recognition twice. He also helped C Dallas Griffin become UT's first Draddy Trophy winner as the top student-athlete in college football in 2007.

A terrific recruiter, McWhorter was able to secure some of the country's top prospects during his time at Texas, including six early commitments in the 2011 recruiting class from players who rank among the nation's best.

"After a long and enjoyable 37 year career in coaching, the last nine at Texas, I have decided to retire," McWhorter said. "This is something that my wife, Becky, and I have talked about for a couple of years. Because of professional and family factors, we feel like the time is right.

"I would like to thank DeLoss Dodds, Mack Brown and everyone associated with The University of Texas for the tremendous experience. I am honored to have been a part of the outstanding success that we have enjoyed at Texas. I will cherish the memories of the National Championship that we won in 2005 and playing for another one in 2009. I feel blessed to have worked with some of the best coaches and men in the profession. Lastly, I have a deep love and appreciation for the players that I have coached and been associated with at Texas. They are a special group."

Tolleson concludes a 37-year coaching career, the last 13 at Texas. Rumors of his retirement have swirled for several years, and word of his decision to step aside had begun to make its way through the team in recent weeks.

Tolleson has turned out some elite defensive tackle talent during his career at Texas (including Casey Hampton, Shaun Rogers, Marcus Tubbs, Rod Wright, Frank Okam, Derek Lokey, Roy Miller, Lamarr Houston and Kheeston Randall) and the position was consistently a team strength.

Tolleson has also been in charge of the Longhorn special teams since 2000, consistently producing kicking and return units that ranked among the country's best. In 2010 though, the Longhorn special teams were a point of frustration for the program.

"It's been a great 13 years. I've really enjoyed the relationships that I've built, especially with the players - it's always been about the players - but also with the administration, staff and alums," Tolleson said. "I love Texas, but right now I feel it's time to step away from coaching. Everybody has been great. It's been a wonderful, wonderful experience, and I am so thankful to have had this kind of time here.

"I want to thank coach Brown and DeLoss Dodds and the staff and everyone I've been associated with, again, especially the players. I've made a lot of friends, and it's been a great experience I'll never forget. I've enjoyed every minute of being a part of the tradition of Texas and everything it stands for - from being around people like coach Royal to the state, The University, the fans - I'll always treasure those things. Having an opportunity to play for the National Championship, it doesn't get any better than that, so it's been the ultimate for me as a football coach to be at a place like The University of Texas."

Speculation continues to swirl on a fourth change, with rumors of wide receivers coach Bobby Kennedy in line to take a position at Colorado under Jon Embree, who was announced as the new CU coach on Monday.

The magnitude of the changes far surpasses anything in Brown's UT career. A coach who prefers unity and has been incredibly loyal to his staff throughout his career, Brown has enjoyed consistency among his assistants during his time in Austin. Most of the coaches that have left have departed for increased roles in other programs or jobs in the NFL, with few coaches actually being asked to step down. This year's changes have a different feel, with Brown having spent considerable time going through tough evaluations of his entire staff once the season ended.

The questions now turn to the future of the Longhorn coaching staff. Numerous sources have indicated that significant funding has been approved as Texas works to fill out its staff.